For many practical applications, it is desirable to detect small numbers of DNA or RNA molecules (collectively xNA) that have a pre-selected sequence from substantial volumes of liquid. For example, xNA molecules from bacteria present in urine can indicate a urinary tract infection. xNA molecules from norovirus from washings from a cruise ship cabin can indicate that decontamination has been incomplete. This requires a step in a workflow process that disrupts cellular and supramolecular structures that may hold the xNA. It also requires a concentration step so as to allow xNA molecules that may be dispersed throughout the substantial volume to be concentrated into a smaller volume. Then, it requires an amplification principle that will create a detectable signal from the very few xNA molecules that might be present in the sample.
At present, procedures to do so involve expensive capture supports, such as those sold by Qiagen, which can cost dollars per sample. Nearly all the workflows associated with these processes include instruments such as centrifuges. Further, since the sample contains (or might contain) a biohazardous microorganism, virus, or other pathogen, it must be run by highly trained personnel.
The realities of modern infectious disease require inventions to do similar things but in low resource environments, at points of sampling, with substantially untrained personnel, and at very low cost. For example, during the Ebola panic, any vomit in airports was potentially a biohazardous substance capable of transferring the disease to maintenance staff and cleanup individuals. Similarly, in high school or college infirmaries, immediate decisions must be made with respect to exotic respiratory viruses, where neither the cost of a Qiagen kit nor the technical expertise needed to handle it are available. Similarly, first responders (such as ambulance personnel) need to be able to evaluate the potential hazards of the pathogen on-site, where the nucleic acid sequence is the defining feature of the pathogen.